Cardiff Blues director of rugby Dai Young believes a number of small errors have been responsible for his side's early Heineken Cup exit after watching them claim a 14-9 win over Castres at Cardiff City Stadium.

The Blues have enjoyed an excellent recent history in Europe, reaching the semi-finals of the Heineken Cup in 2009 before winning the Amlin Challenge Cup last season. Hopes had been high that they could challenge for honours in the top-tier competition this term, but three defeats from their opening four games meant the best they could hope for from their final two Pool One games was a runner-up spot and a place in the last eight of the Amlin Challenge Cup.

Tonight's win, courtesy of a Leigh Halfpenny try and three penalties from Dan Parks, keeps them in with a chance of that second-place spot with just their trip to Edinburgh remaining. But they may be left to rue allowing their French visitors to secure the losing bonus point which leaves them in that second place, a point above the Blues, with one round of games to go.

And Young lamented some of the mistakes that have cost his side in Europe. "Over the last couple of seasons, a lot of the games we won in Europe were close, and now we're losing by small margins," he said. "It's not been a massive swing.

"Missed penalties, missed kicks to touch, the little things that were going right last year have been going wrong. We talk about nailing opportunities, and it never really happened tonight. When you get to a position like 11-3 up, and you've got to kick on, but we couldn't get the extra scores that would have allowed us to relax."

Young acknowledged that many of his players are nearing the end of their careers, and promised there would be changes come the end of the season. "We have an old squad, and we've got to look at addressing that," he said. "It's not going to be easy next season, with the World Cup, so it'll be a two-year operation. We won't be casting anyone aside, but we've got to start pushing youngsters through. There's going to be a changing of the guard."

But Young did reserve praise for Wales wing Halfpenny, who has now scored two tries in two starts since returning from an ankle ligament injury. "Leigh looked a threat every time he had the ball," said Young. "He's a quality player, and he's full of enthusiasm after being out injured. It's good news for Wales coach Warren Gatland, because he's a match-winner."